The invention relates to an apparatus accommodated in a housing or box, for processing sheet-like layers in the form of webs which are passed through the apparatus, by means of spark discharge between an electrode in the form of a roller and an opposed electrode arranged axially parallel thereto, one electrode being carried by a lid of the box.
An apparatus of this type is known from German Utility Model No. 7328009. Its function is to protect from contact, and in it the lid is joined to the box by a hinge, so that the lid can be raised into an inclined position to enable a web to be inserted. This arrangement has been found to have the drawback that a space is required above the box to enable it to be opened by raising the lid, and such a space is not always available.